Layout instruments, including squaring devices, are known for squaring the positioning of walls, laying out and squaring building foundations, squaring framework etc. It has been proposed to mount two or more measuring tapes on a common support to provide various instruments and devices for this purpose.
However, these prior proposals in general involve procedures that require a level of trained skill, such as effecting accurate measurements, making calculations, having a knowledge of the 3-4-5 triangle, etc.